Can the pill impact who women choose to date, or have kids with?

The emergence of the birth control pill in 1960 is largely credited with ushering in a new era of female sexual independence. In the decades since the pill has become a standard component of many women’s contraceptive routines—100 million women worldwide currently take the birth control pill, according to United Nations estimates. Yet, in spite of the widespread use of birth control pills, which work by mimicking the hormonal state of pregnancy and effectively putting the ovaries to sleep, a new study published in the October issue of the journal Trends in Ecology and Evolution, posits that the persistent use of hormones may be influencing women’s love lives in ways other than reducing acne or alleviating cramps.

Researchers at the U.K.’s University of Sheffield reviewed the latest research and suggest that, because the menstrual cycle—and its fluctuating hormones—has, evolutionarily speaking, long played a significant role in influencing sexual attraction, overriding those hormonal ups and downs with the pill may actually be altering women’s preferences when it comes to dating, or having kids. “New evidence is now emerging that taking the oral contraceptive pill might significantly alter both female and male mate choice by removing the mid-cycle change in preferences,” they write.

What preferences, exactly, are impacted? From the male perspective, a handful of studies have shown that, whether they’re aware or not, men tend to find ovulating women more attractive than those in other parts of their cycles. (A 2007 study conducted by psychologists at the University of Mexico found that strippers earned more in tips while they were ovulating, for example.) The implication of this finding, of course, is that women on the pill—who don’t experience the hormonal surges around ovulation—would be at a disadvantage in competing for mates against women not using the birth control pill, the researchers say.

Additionally, the study found that, in the days surrounding ovulation women tend to find more “manly” looking men attractive, prefer guys who seem to be more competitive with their male peers, and opt for mates who look the least like themselves. This last point is particularly important, the researchers say, as some preliminary research has linked too much genetic similarity between partners with possible infertility.